High pressure and high flow valves are used in a variety of applications. For example, clinical laboratories and hospitals utilize various diagnostic apparatuses to analyze patient medical samples, such as blood, urine, other fluids, and tissues. Such applications further include portable medical devices that aid breathing, such as oxygen concentrators and infiltrators. In such apparatuses, high pressure and high flow valves control the flow of gases or other fluids. Because it is desirable for such apparatuses to be as compact as practicable, the size of the valves remains a concern, but with reduced size sufficient speed and efficiency needs to be maintained.
Solenoid valves with an electromagnetically driven actuator may be employed in high pressure and high flow applications. Higher flow and pressure capabilities typically require a larger valve actuator to develop the sealing force needed for valve operation, which poses a significant challenge in balancing size and performance. To achieve higher flow, a larger orifice is required, and consequently a larger stroke to allow full flow to develop. However, this requires more magnetic attraction force from the actuator to overcome the large air gap.
Some improvement in the magnetic attraction force that drives the actuator can be made through magnetic material selection, but the performance difference between materials that are readily available and cost effective is limited. Additional improvements in attraction force can be made through increased coil power and number of wire turns, but there are diminishing returns once the soft magnetic materials have been saturated with the magnetic flux, and peak power budgets must also be considered. Increasing cross-sectional area of the flux path components allows more flux to be carried and thus increases the magnetic attraction force, but this must be balanced against the desire to reduce the valve size and weight for portability. Accordingly, it has proven difficult to reduce valve size while maintaining efficient performance at the requisite high flows and pressures of solenoid actuator valves.